This suggests that Trump’s takeover of the Republican Party is not only hostile, but — as with his party-hopping forerunner Michael Bloomberg in NYC — temporary.

It would be difficult to overstate the significance of a “Republican” presidential candidate deliberately sabotaging attempts by the GOP to hold onto the Senate and House. Normally it is far easier for a president to advance his agenda if his party holds Congress. Possible explanations include:

1. Trump has no intention of governing as a Republican. The ruse of portraying himself as a parodic version of one having served its purpose, he will discard it upon taking power, probably even faster than his role model Michael Bloomberg did. Even if he does not officially switch parties again after taking power, Trump’s Big Government agenda will encounter little resistance from Democrats — or from most remaining Republicans either, no matter how badly he treats them, if recent history is a guide.

2. Trump does not need a legislature, because he plans to rule as a dictator. This one is less likely, but he did proclaim during a primary debate that he would rule by unlawful decree as he sees fit.

3. Trump’s personality is so fundamentally flawed that he cannot restrain from lashing out at anyone he sees as challenging him, no matter how suicidal this behavior may be.

4. Trump knows as well as anyone that he is going to lose, and ignobly wants to take down as many as he can with him.

The actual reason for Trump’s astonishing behavior is probably a combination of the above. If there is an honorable, benevolent, or constructive explanation, I have never heard it.

There is only one course of action, and an increasing number of prominent Republicans have found the nerve to take it. Cut Trump loose, mitigate the long-term damage by making it clear to voters that you want nothing to do with him, and rebuild the party when this nightmare is over — if there is enough left of it to rebuild.